Costafrolaz J, Panis G, Casu B, Ardissone S, Degeorges L, Pilhofer M, Viollier PH. Adaptive β-lactam resistance from an inducible efflux pump that is post-translationally regulated by the DjlA co-chaperone.
PLoS Biol 2023;
21:e3002040. [PMID:
38051727 PMCID:
PMC10754441 DOI:
10.1371/journal.pbio.3002040]
[Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2023] [Revised: 12/28/2023] [Accepted: 10/19/2023] [Indexed: 12/07/2023] Open
Abstract
The acquisition of multidrug resistance (MDR) determinants jeopardizes treatment of bacterial infections with antibiotics. The tripartite efflux pump AcrAB-NodT confers adaptive MDR in the polarized α-proteobacterium Caulobacter crescentus via transcriptional induction by first-generation quinolone antibiotics. We discovered that overexpression of AcrAB-NodT by mutation or exogenous inducers confers resistance to cephalosporin and penicillin (β-lactam) antibiotics. Combining 2-step mutagenesis-sequencing (Mut-Seq) and cephalosporin-resistant point mutants, we dissected how TipR uses a common operator of the divergent tipR and acrAB-nodT promoter for adaptive and/or potentiated AcrAB-NodT-directed efflux. Chemical screening identified diverse compounds that interfere with DNA binding by TipR or induce its dependent proteolytic turnover. We found that long-term induction of AcrAB-NodT deforms the envelope and that homeostatic control by TipR includes co-induction of the DnaJ-like co-chaperone DjlA, boosting pump assembly and/or capacity in anticipation of envelope stress. Thus, the adaptive MDR regulatory circuitry reconciles drug efflux with co-chaperone function for trans-envelope assemblies and maintenance.
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